Over the years there has been developed a range of drive line capabilities. For example, there is two-wheel drive only, full-time four-wheel drive and two-wheel/four-wheel optional drive, i.e., the driver can elect as desired either two-wheel drive or four-wheel drive. The latter type of drive is somewhat more expensive because it requires the drive line components for driving all four wheels and also requires the disconnect mechanism typically at both the transmission and wheel end for disconnecting the non-functional drive line components when converted to two-wheel drive.
The same vehicle design may be desired for both two-wheel/four-wheel optional drive and full-time four-wheel drive. There are cost savings that can be realized in the design of the full-time four-wheel drive system over that of the two-wheel/four-wheel optional drive, i.e., the disconnect mechanism can be eliminated. Thus, there are fewer parts to produce and install resulting in savings of parts production costs and installation costs.
Ideally the drive and driven shafts required for converting between two-wheel and four-wheel drive are replaced with a single shaft. The clutch ring and actuator are eliminated and of course the need to assemble these components is also eliminated. Offsetting these advantages however is the need to design, produce and test a new drive line system which can be a major expense.
Accordingly, it is an object of the present invention to enable the use of the same drive line design for the same vehicle whether for full-time four-wheel drive or four-wheel/two-wheel optional drive while substantially reducing the cost of the drive line of the full-time four-wheel drive option, i.e., to a point close to the level of the cost of using a one-piece axle.